The RSS Reader is a software application that assist users easily to read and collect contents which are frequently changeable syndicated contents of RSS format that published on the web. This paper presents a formula software design based on RUP object-oriented design method for implementing the RSS Reader. We extract a use case based on requirements for implement of the RSS Reader and propose a domain concept model by. Using above artifacts, we extract event to generate between users and, the RSS Reader and logical architecture. So, we design classes and packages of the RSS Reader. As proposed a formula software design about the RSS Reader in early stage, it can make the RSS Reader with a variety of characters easily based on these.